User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.4) Gecko/20060406 Firefox/1.5.0.4 (Debian-1.5.dfsg+1.5.0.4-1)
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.4) Gecko/20060406 Firefox/1.5.0.4 (Debian-1.5.dfsg+1.5.0.4-1)

if you didn't start fcitx(a chinese input method) while starting X,
and after a while,
you wish to use it.
In a terminal you run the fcitx. then, xfce-mcs-manager would probably quits.

Reproducible: Always